Art of cracking hydrocarbons



Aug. v23, 1932. C HERTHEL 1,872,949

ART OF CRACKING HYDROCARBONS Original Filed April 4, 1930 INVENTOR v Eye/7e C fler ffie/ ATTORNEYS v Patented Aug. 23, 1932 *T'AUNITiED EUGENE o. HERTHEIJ, F rnossnco on, ILLINOIS; As'sreivo'n T0 snv'omim "R FI I G COMIPANY, OF-NEW YORK, my A-oonronArioN or Marni: '7

ART; or onaoxnve jHYDnooARBoNs Application fired April 4, 1930, Serial This invention relates to improvements in i the "manufacture of lower boiling hydrocarbon' oils, such as gasoline, from higher boiling V hydrocarbon oils, such as gas oil and reduced crude 011, by crackmg operations.

The present invention provides an im: proved method and apparatus of special value and application for heating hydrocarbon oils tocracking temperatures in carrying out op- 19 erations in which high boiling oil isheated to a cracking temperature under high pressure and in which the hot oil products of this heating operation are separated into a vaporized fraction and anunvaporizedfraction under lower pressure, or so-called pressure coil? cracking operations. 'The improved method 7 and apparatus ofthe invention, however, are of general application for heating hydrocarbon oils to cracking temperatures.

In one aspect, this invention includes improvements on the invention described in my application filed February 8, 1930, Serial No.

426,901 now U. S. Patent 1,809,297.

According to this invention, the oil is heated to a cracking temperature by circulation thru a plurality of heating tubes in a heating chamber arranged, with respect to the combustion chamber in which fuel is burned for supplying heat to the operation, so that the 33 heating tubes in the heating chamber are heated both by sensible heat absorbed from the heating gases from the combustion chamber, the hot gaseous products of combustion, and by radiant heat transmitted from the Z75 combustion chamber thru a wall or baflie adapted to transmit radiant heat but to prevent flame impingement on the heating tubes in the heating chamber by compelling the heating gases from the combustion. chamber to pass to the heating chamber along a path substantially longer than that along which radiant heat is transferred from the combustion chamber to the heating chamber. The invention will be further described in connection with the accompanyingdrawing which illustrates, diagrammatically and conventionally, in elevation and partly in section and with parts broken away, one form of apparatus embodying the invention and adapted L1 for carrying out the invention.

no. Mite-4.1 iiezieweai may 21-,- 1932'. t

In out so-ca ll ed pressure coil cracking operations in the apparatus llustrated, for example, a stream of high boiling 6111 is forced, by means or" pump 1,;thru'the heating tubes2, connected to form acontinu o'us'heating conduit, arranged the heating chamber 3, the hot oil products from the heating tubes 2 being discharged thru Comtetion 4,includin'g apressure regulating andrIe ducing valve5, to a suitable vapor separating receptacle, the oilbeingjheated to. a Cracking temperature during passage thruthe heating 7- tubes 2. Oil cooler than thehot-oilproducts discharged thrutheconnection l may, be in;

troduced thr'u the connectionifi, to.) arrest the cracking reaction" initiated, in "the heating tubes 2,.and'supplied .to' the vapor separating receptacle with these l10l3-0ll product's, In'the heating tubes 2,.the oilcm ayibe heated tola 7 i temperature approximatingv87 5-97 5- F un= der a pressure apprOXimatingQOO-sGOOpounds perfsquare inch, as discharged therefrom, for example.

Thefurnace of apparatus illustrated comprises the heating. chamber 3 and. the. combustion chamber 7, this heating chamber and this combustion chamber being sepa rated by, but only by, a wall or battle 8, in the form of abridge-wall, ada ted to trans' mit radiant heat from'the com ,ustionchamher 7 to the heating chamber 3 and lto. cornpel the hot gas-eousproducts of combustion fromthe combustion chamber topass to the heatingchamber thru a flue. 9, one boundary of which is the .wall 8 A stack flue l0,com municating with the heating chamber atthe end; opposite that atwhich the flue ,9 communicates-therewith is provided for the dis chargeof heating gasesfrom'thejcombustion chamberr Fuel and air are supplied to the oombustione chamber in the usual manner,

by means of. the

burner 11 in the-apparatus illustrated. i v a I The wall 8 may, for example, be oiirefrac tory metal, any of the ,known heat resistant alloys, for example. ll

In the apparatus illustrated, radiant heat V is transmitted along a" relatively short pathl from-the combustion chamber 7 thru the wall 8 to the heating ohainber3. V The seniao' ing chamberS along. a path substantially longer than that along which radiant heat a is transferred from the combustion-chamber 7 to the heating chamber 3, a path long heating tubes 2, 5 g

r The furnace may, with advantage, be arranged and operated as describedin'Lettersg enough to avoid flame impingement upon the 7 Patent Nos. 1,574,546, and l,57l,5t7,.issued to Sinclair Refining Company, February 23,-"

1926, on applications of the lateJohn E.

Bell, ora'sdescribed in Letters PatentfNo. 1,623,773 issued to Sinclair Refining Com-z pany, April 5', 1 927, onapplication of the late John E. Bell-. The recirculation of heating gases thru the heating I chamber, in [conjunction with" this invention, is particularly advantageous in minimizing any tendency, toward" local overheating within the heating chamber and in improving the rate of ab sorptionof sensible heat therein. The use of preheatedairfor combustion, in conjunction with this invention, is particularly ad vantage'ous in that it improves the rate of transmission oi' radia'nt heat from the combustioni chamber tothe heating chamber by affording higher combustion temperatures.

- The heating chamber may be provided Witha bafile 12, as described inmy applica- 1 tion Serial No; 426,90l mentioned above. Thebafile 12, of refractory-metal forfex- V V ample,-is arranged generally para'llel to and spaced from the wall 8 subdividing the heating tubes 2 into two groups, one group between the baffle 12 and the wall Sand the other group on the other'side of the baflie 12.

The bafile .12 extends entirely. across the heating chamber but is arranged to leave passages for heating gases across the upper and lower ends of the'heating chamber. By

adjusting the areas of these passages and the, relative areas of these "passages the ratio between the rates at which heat is absorbed by the firstv group'o'f heating tubes and by thesecond group of he'atingtubes .ma ,Iybe increased or decreased.

e particular arrangement of apparatus illustrated isof special valueand applica-' 131011 incarrying "out operations-fin which oil is to bebrought quickly to a. high cracking "temperature'and then maintained at that temperature'or at a temperature progressively increasing Or'decreasing therefrom for a fixed period of time. The oilis supplied first to the group of heating tubes absorbing heat atthe highest rate, those most' exposed to radiant "heat, the group of heating tubes between'the bafl le' 12 and the wall 8, I

and is then passed thru the remaining heat-,

' ing tubes. The oil' is'thus brought quickly to a high cracking temperature in a region in which the heat'absorption rate is high and is then circulated thru heating tubes in a region in which thevheat absorption rate is r to lower. v a e V "The advantages'of the invention include particularly improvements in both capacity and efficiency. I

In apparatus for heatin'g hydrocarbon-oils tocracking temperatures, a combustion chamber and a heating chamber separated by and'on'ly' byia wall adaptedto transmit I radiant heat 'from said combustion chamber t'o said heating chamber and-l'connected by a flue for passage of hot gaseous products of combustioniro n saidcombustion c'ham-Q which radiant heatis transferred from said combustion.chamber to said heating chamber thru. said wall, means for supplying fuel and air to the combustion chamber and means for. discharging heating gases from ber to said heating chamber but along a path substantially? longer than the path along ing tubes arranged in the heating chamber,

and afbaifie generally parallelito'an'd spaced from said wall dividing said oi l heating tubes into two groups, one between said'baflle side of said baille. Y

I In'te'stim'ony whereoflaffix mysignature;

and said wall and. the other onlthe other V t PEUGENECL .HE L- the heating chamber,aplurality of oil heat 

